In relation to housing which is an object of cooling, heat-generating equipment is generally housed in a sealed enclosure. The enclosure has a narrow space which inhibits entry of a person. Equipment housed in the enclosure has heat-generating components and hence is cooled appropriately.
A cooling system described in Japanese Patent Application Laid-Open No. 041503/2001 is mentioned as a cooling system for cooling the inside of such an enclosure. FIG. 9 shows the cooling system.
As shown in FIG. 9, an enclosure cooling system 51 of a housing 52 is configured to cool the inside of an enclosure 53 of the housing 52 that forms a closed space, by means of an auxiliary cooling device indoor unit 59 and an auxiliary cooling device outdoor unit 60, which are closed with a natural circulation refrigerant circuit 65; and a main cooling device indoor unit 61 and a main cooling device outdoor unit 62, which are closed with a forced circulation refrigerant circuit 66 for forcefully circulating refrigerant with a compressor 74. Heat-generating equipment 54 including heat-generating components is housed in the enclosure 53.
In the case of the common heat-generating equipment 54, a fan (not shown) is provided within an equipment case 56 which houses a heat-generating component 55. Air is taken into the case from an air intake 57 provided in a side surface or bottom surface of the case. Hot air is issued from an air outlet 58 provided in an upper portion of the case. The enclosure 53 has an outside air inlet ventilation fan 63 and an exhaust damper 64 for preventing an internal temperature of the enclosure from exceeding a given level in the event of occurrence of an anomaly in the enclosure cooling system. Cooling capacity of the conventional cooling system is determined so as to meet the maximum load of the heat-generating component 55. The enclosure 53 usually has a structure which involves considerably low heat transmission. Hence, variations in outside air temperature do not cause any substantial variations in cooling load in the enclosure 53.
Operation of the enclosure cooling system 51 of the housing 52 will now be described.
During normal operation, cool air located at a position “B” on the side of the equipment case 56 is taken into the case from the air intake 57, by means of driving of a fan (not shown) provided in the heat-generating equipment 54. The thus-taken-in cool air cools the heat-generating component 55, to thereby become hot air. The hot air is blown from the air outlet 58 provided in an upper portion of the case to a position “C” within the housing 53. In this way, the thus-issued hot air is taken into the auxiliary cooling device indoor unit 59 from a position “D” by way of a hot air intake 70 by means of blowing action of a main cooling device indoor unit fan 67. The hot air is subjected to primary cooling by exchanging heat with refrigerant of the natural circulation refrigerant circuit 65. After having been blown by the main cooling device indoor unit fan 67 through suction, a total amount of the air located at a position “E” that has been subjected to primary cooling passes through a main cooling device indoor unit evaporator 72, where heat is exchanged with the refrigerant of the forced circulation refrigerant circuit 66, and hence the air is cooled. The thus-cooled air is blown as cool air from a cool air outlet 71 to a position “A” within the enclosure 53. Namely, the air cools the inside of the enclosure 53 by sequentially circulating through positions “A, B, C, D, and E”.
When the main cooling device indoor unit fan 67 becomes inoperative for reasons of a failure or when no power is supplied to the main cooling device indoor unit fan for reasons of a power failure, the heat-generating equipment 54 operates at all times by means of a backup power supply (not shown). However, since the cooling system becomes inoperative, the internal temperature of the enclosure 53 increases. Temperature detection means 73 for detecting an anomaly is provided within the enclosure 53. When the temperature detected by the temperature detection means 73 has exceeded a certain temperature (e.g., 40° C.), the ventilation fan 63 and the exhaust damper 64 operate, to thereby simultaneously take in outside air and exhaust air from the inside of the enclosure 53. If the temperature detected by the temperature detection means 73 continuously increases (to, e.g., 45° C.) despite the exhausting operation, a warning is issued to a control center. Thus, the cooling system operates in two steps.
Such a conventional cooling system is constituted of four components; namely, a main cooling device, an auxiliary cooling device, a ventilation fan, and an exhaust damper. Further, the dimensions of the enclosure have already been determined. Hence, a detailed review is required to determine locations of the respective components. Particularly, the auxiliary cooling device indoor unit is equipment for enhancing an energy saving characteristic. Setting the auxiliary cooling device indoor unit in the vicinity of an air outlet of heat-generating equipment results in a greater effect but poses a problem of limitations of space.
The ventilation fan is for protecting heat-generating equipment in the event of an anomaly in the cooling system. Hence, setting the ventilation fan close to the heat-generating equipment is preferable, as in the case of the auxiliary cooling device indoor unit. Thus, setting pieces of equipment at a single position is desirable, and hence assignment of installation places requires consumption of time at the time of examination of a layout which yields system effectiveness. Moreover, a plurality of pieces of equipment are disposed outside the enclosure, which induces projections and depressions and impairs the appearance of the cooling system.
The conventional cooling system requires a large number of pieces of constituent equipment, which involves complicated setting work. Particularly, an auxiliary cooling device is of a refrigerant natural circulation system. Hence, if piping work is not appropriately laid such that a refrigerant pipe for connecting an outdoor unit with an indoor unit is sloped forward, the cooling system will fail to exhibit cooling capability.
The invention has been conceived to solve such a conventional problem and aims at providing a cooling system which simplifies the design of facilities and setting work by housing a plurality of heat exchange means, which constitute a cooling system, in one enclosure and making them operative; which makes an attempt to save energy by appropriately controlling a plurality of heat exchange means; and which prevents occurrence of a cooling failure, which would otherwise be associated with a failure in installation work.